Research Database
Displaying 21 - 40 of 40
Did the 2002 Hayman Fire, Colorado, USA, Burn with Uncharacteristic Severity?
Year: 2016
There is considerable interest in evaluating whether recent wildfires in dry conifer forests of western North America are burning with uncharacteristic severity—that is, with a severity outside the historical range of variability. In 2002, the Hayman Fire burned an unlogged 3400 ha dry conifer forest landscape in the Colorado Front Range, USA, that had been the subject of previous fire history and forest age structure research. We opportunistically leveraged pre-existing data from this research, in combination with post-fire aerial imagery, to provide insight into whether the Hayman Fire’s…
Publication Type: Journal Article
A state-and-transition simulation modeling approach for estimating the historical range of variability
Year: 2015
Reference ecological conditions offer important context for land managers as they assess the condition of their landscapes and provide benchmarks for desired future conditions. State-and-transition simulation models (STSMs) are commonly used to estimate reference conditions that can be used to evaluate current ecosystem conditions and to guide land management decisions and activities. The LANDFIRE program created more than 1,000 STSMs and used them to assess departure from a mean reference value for ecosystems in the United States. While the mean provides a useful benchmark, land managers and…
Publication Type: Journal Article
Temperate forest health in an era of emerging megadisturbance
Year: 2015
Although disturbances such as fire and native insects can contribute to natural dynamics of forest health, exceptional droughts, directly and in combination with other disturbance factors, are pushing some temperate forests beyond thresholds of sustainability. Interactions from increasing temperatures, drought, native insects and pathogens, and uncharacteristically severe wildfire are resulting in forest mortality beyond the levels of 20th-century experience. Additional anthropogenic stressors, such as atmospheric pollution and invasive species, further weaken trees in some regions. Although…
Publication Type: Journal Article
Increasing weight of evidence that thinning and burning treatments help restore understory plant communities in ponderosa pine forests
Year: 2015
For more than a century ecosystems around the world have experienced an increase in the dominance of woody species. While the drivers of woody plant proliferation are complex, interactions between climate and land-use change are commonly invoked as primary contributing factors. In ponderosa pine forests of western North America, substantial increases in tree densities are impacting overall forest health and increasing the risk for severe wildfires and insect and disease outbreaks. Addressing this problem through the use of ecological restoration projects is widely advocated. Our objective was…
Publication Type: Journal Article
Does wildfire likelihood increase following insect outbreaks in conifer forests?
Year: 2015
Although there is acute concern that insect-caused tree mortality increases the likelihood or severity of subsequent wildfire, previous studies have been mixed, with findings typically based on stand-scale simulations or individual events. This study investigates landscape- and regional-scale wildfire likelihood following outbreaks of the two most prevalent native insect pests in the US Pacific Northwest (PNW): mountain pine beetle (MPB; Dendroctonus ponderosae) and western spruce budworm (WSB; Choristoneura freemani). We leverage seamless census data across numerous insect and fire events to…
Publication Type: Journal Article
An Evaluation of Fire Regime Reconstruction Methods
Year: 2014
Ecological restoration is a practice that seeks to heal degraded ecosystems by reestablishing native species, structural characteristics, and ecological processes. The Society for Ecological Restoration International defines ecological restoration as “an intentional activity that initiates or accelerates the recovery of an ecosystem with respect to its health, integrity and sustainability….Restoration attempts to return an ecosystem to its historic trajectory” (Society for Ecological Restoration International Science and Policy Working Group 2004). Most frequent-fire forests throughout the…
Publication Type: Report
Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival
Year: 2014
Fuel treatment implementation in dry forest types throughout the western United States is likely to increase in pace and scale in response to increasing incidence of large wildfires. While it is clear that properly implemented fuel treatments are effective at reducing hazardous fire potential, there are ancillary ecological effects that can impact forest resilience either positively or negatively depending on the specific elements examined, as well as treatment type, timing, and intensity. In this study, we use overstory tree growth responses, measured seven years after the most common fuel…
Publication Type: Journal Article
Contemporary forest restoration: A review emphasizing function
Year: 2014
The forest restoration challenge (globally 2 billion ha) and the prospect of changing climate with increasing frequency of extreme events argues for approaching restoration from a functional and landscape perspective. Because the practice of restoration utilizes many techniques common to silviculture, no clear line separates ordinary forestry practices from restoration. The distinction may be that extra-ordinary activities are required in the face of degraded, damaged, or destroyed ecosystems. Restoration is driven by the desire to increase sustainability of ecosystems and their services and…
Publication Type: Journal Article
Managing burned landscapes: Evaluating future management strategies for resilient forests under a warming climate
Year: 2014
Climate change effects on forested ecosystems worldwide include increases in drought-related mortality, changes to disturbance regimes and shifts in species distributions. Such climate-induced changes will alter the outcomes of current management strategies, complicating the selection of appropriate strategies to promote forest resilience. We modelled forest growth in ponderosa pine forests that burned in Arizona’s 2002 Rodeo-Chediski Fire using the Forest Vegetation Simulator Climate Extension, where initial stand structures were defined by pre-fire treatment and fire severity. Under extreme…
Publication Type: Journal Article
Western Spruce Budworm Outbreaks Did Not Increase Fire Risk Over the Last Three Centuries: A Dendrochronological Analysis of Inter-Disturbance Synergism
Year: 2014
Insect outbreaks are often assumed to increase the severity or probability of fire occurrence through increased fuel availability, while fires may in turn alter susceptibility of forests to subsequent insect outbreaks through changes in the spatial distribution of suitable host trees. However, little is actually known about the potential synergisms between these natural disturbances. Assessing inter-disturbance synergism is challenging due to the short length of historical records and the confounding influences of land use and climate changes on natural disturbance dynamics. We used…
Publication Type: Journal Article
Eastern Washington Forest Health: Hazards, Accomplishments and Restoration Strategy
Year: 2014
Much of the 10 million acres of forestland in eastern Washington faces serious threats to forest health. Decades of fire suppression and past management practices that changed the species and structure of these forests have put them at higher risk of damage by disease, insects and wildfire.
Publication Type: Report
Historic Variability: Informing Restoration Strategies, Not Prescribing Targets
Year: 2014
The concept of historic range of variability (HRV) is briefly evaluated within the context of its application in ecosystem management over the past two decades. Despite caveats to the contrary, an implicit assumption continues to emerge of climatic stationarity, and, by corollary, that presettlement centuries provide an appropriate reference period. This is examined from the perspective of historic climate change and ecosystem response. As a means of developing reference prescriptions and management targets, HRVis generally inappropriate, although if historic periods are used for…
Publication Type: Journal Article
Swiss Needle Cast
Year: 2013
Since the 1990s, there has been an epidemic of SNC affecting hundreds of thousands of acres of coastal Douglas-fir forests in Oregon, Washington and British Columbia. This constitutes one of the largest foliage-disease epidemics of conifers in North America. SNC is also a localized problem in many inland areas of the west, especially in Montana, Idaho, British Columbia, Washington, and Oregon.
Publication Type: Report
Projected Future Changes in Vegetation in Western North America in the Twenty-First Century
Year: 2013
Rapid and broad-scale forest mortality associated with recent droughts, rising temperature, and insect outbreaks has been observed over western North America (NA). Climate models project additional future warming and increasing drought and water stress for this region. To assess future potential changes in vegetation distributions in western NA, the Community Earth System Model (CESM) coupled with its Dynamic Global Vegetation Model (DGVM) was used under the future A2 emissions scenario. To better span uncertainties in future climate, eight sea surface temperature (SST) projections provided…
Publication Type: Journal Article
Long-term perspective on wildfires in the western USA
Year: 2012
Understanding the causes and consequences of wildfires in forests of the western United States requires integrated information about fire, climate changes, and human activity on multiple temporal scales. We use sedimentary charcoal accumulation rates to construct long-term variations in fire during the past 3,000 y in the American West and compare this record to independent firehistory data from historical records and fire scars. There has been a slight decline in burning over the past 3,000 y, with the lowest levels attained during the 20th century and during the Little Ice Age (LIA, ca.…
Publication Type: Report
Characterizing Fire-on-Fire Interactions in Three Large Wilderness Areas
Year: 2012
The interaction of fires, where one fire burns into another recently burned area, is receiving increased attention from scientists and land managers wishing to describe the role of fire scars in affecting landscape pattern and future fire spread. Here, we quantify fire-on-fire interactions in terms of frequency, size, and time-since-previous fire (TSPF) in three large wilderness areas in Montana and Idaho, USA, from 1984 to present, using spatially consistent large fire perimeter data from the Monitoring Trends in Burn Severity (MTBS) dataset. The analysis is supplemented with less consistent…
Publication Type: Journal Article
Communication of the Role of Natural Variability in Future North American Climate
Year: 2012
As climate models improve, decision-makers' expectations for accurate climate predictions are growing. Natural climate variability, however, poses inherent limits to climate predictability and the related goal of adaptation guidance in many places, as illustrated here for North America. Other locations with low natural variability show a more predictable future in which anthropogenic forcing can be more readily identified, even on small scales. We call for a more focused dialogue between scientists, policymakers and the public to improve communication and avoid raising expectations for…
Publication Type: Journal Article
Assessing tree health
Year: 2011
Healthy trees are beneficial to our environment and our property values - but how do we determine if a tree is healthy? This publication briefly discusses common tree health problems and outlines a procedure for assessing tree conditions and getting diagnoses and recommendations from tree health professionals.
Publication Type: Report
Reducing Fire Risk on Your Forest Property
Year: 2010
Whether you own a few acres or thousands, this publication will help you reduce the potential for wildfire damage on your property while improving overall forest health and wildlife habitat. Although these actions won’t prevent a wildfire from coming onto your property, they can make it more fire resistant. In other words, by following the guidelines in this publication you can reduce a fire’s severity so that most trees survive and firefighters are better able to attack and extinguish the blaze. While this publication provides suggestions for making your property more fire-resistant, it does…
Publication Type: Report
A Tale of Two Cedars: International Symposium on Western Redcedar and Yellow-Cedar
Year: 2010
From May 24-28, 2010, an international symposium on western redcedar (Thuja plicata) and yellow-cedar (Callitropsis nootkatensis [syn. Chamaecyparis nootkatensis]) was held at the University of Victoria on Vancouver Island in British Columbia, Canada. The symposium was entitled “A Tale of Two Cedars” and brought together local, regional, national, and international experts to present cultural, biological, management and economic information on the two species. Although some papers or posters focused on just one of the cedars, many of the presenters covered both species and discussed the…
Publication Type: Report